General English

General Science

  • noun a paper packet that contains a letter or document
  • noun the name for the data which contain a mail message with the destination address information


  • noun the set of limitations within which a technological system, especially an aircraft, can perform safely and effectively

Cars & Driving

  • noun a cover enclosing something entirely, such as the glass of a lamp bulb


  • noun a transmitted packet of data containing error detection and control information
  • noun the shape of the decay curve of a sound
  • noun the data which contains a mail message with the destination address information


  • A term used to denote the extreme outside surface and dimensions of a building.
  • An assembly of planes representing the limits of an area that may house a structure, i.e., a zoning envelope.


  • The outermost points traced out by a moving curve.


  • A glass housing which encloses the elements of electric lamps, electron tubes, and similar devices. An envelope may or may not be evacuated. Also called bulb (1).
  • A curve whose points pass through the peaks of a graph, such as that showing the waveform of an amplitude-modulated carrier.
  • That which serves to encompass or surround, such as the outer sheath of a cable.
  • The bounds within which an entity or system can be operated. For instance, the range of motion of a robotic end-effector.
  • In communications, a group of bits, or other information-carrying entity, treated as a unit.

Health Economics

  • (written as Envelope)
    Usually refers to a smooth curve that is tangential to each of a family of curves or a frontier marking the boundary between what is possible with given technologies and resources and what is not.

Information & Library Science

  • noun a paper cover which can be sealed and used to send a letter through the post

Origin & History of “envelope”

English borrowed envelope from French enveloppe in the sense ‘wrapper’, and more specifically ‘cover for a letter’, at the start of the 18th century. It was a derivative of the verb envelopper ‘wrap’, whose ancestor, envoloper, gave English envelop in the 14th century. As in the case of its first cousin develop, the origin of the verb remains a mystery. It is a compound formed from the prefix en- ‘in’ and voloper ‘wrap’, but the source of voloper has never been satisfactorily explained. It may come from a hypothetical Celtic base *vol- ‘roll’, but an equally good candidate is late Latin *faluppa ‘husk’, from which come Italian viluppo ‘bundle’ and viluppare ‘wrap’.